Probe for high frequency signals

Abstract

A high frequency probe has contact tips located within the periphery of a terminal section of a coaxial cable and shielded by a ground conductor of the coaxial cable.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 688,821, filed Jun. 8, 2005.BACKGROUND OF THE INVENTION[0002]The present invention relates to probe measurement systems for measuring the electrical characteristics of integrated circuits and other electronic devices operated at high frequencies.[0003]There are many types of probing assemblies that have been developed for the measuring the characteristics of integrated circuits and other forms of microelectronic devices. One representative type of assembly uses a circuit card on the upper side of which are formed elongate conductive traces that serve as signal and ground lines. A central opening is formed in the card, and a needle-like probe tip is attached to the end of each signal trace adjacent the opening so that a radially extending array of downwardly converging needle-like tips is presented by the assembly for selective connection with the closely spaced pad...

AI Technical Summary

Benefits of technology

The solution effectively reduces cross-talk and extends the usable frequency range by minimizing electromagnetic radiation and increasing current carrying capacity, providing improved performance at higher frequencies with reduced crosstalk and enhanced shielding.

Problems solved by technology

Accordingly, a probing assembly of this type is unsuitable for use at microwave frequencies due to the high levels of signal reflection and substantial inductive losses that occur at the needle-like probe tips.

However, this approach has resulted in only limited improvement in higher frequency performance due to various practical limitations in the construction of these types of probes.

As a practical matter, however, it is difficult to join the thin vertical edge of each blade to the corresponding trace on the card while maintaining the precise face-to-face spacing between the blades and the correct pitch between the ends of the needle-like probe tips.

The probing assembly shown in Lockwood et al. fails to provide satisfactory electrical performance at higher microwave frequencies and there is a need in microwave probing technology for compliance to adjust for uneven probing pads.

However, the Drake et al. probing assembly has insufficient performance at high frequencies.

While the structures disclosed by Burr et al. are intended to provide uniform results over a wide frequency range, they unfortunately tend to have non-uniform response characteristics at high microwave frequencies.

However, at high frequencies, approximately 220 GHz and greater, the length of the conductive interconnection between the probe tip and the coaxial cable connection becomes a significant fraction of the wavelength of the signal and the interconnection acts increasingly as an antenna, emitting increasingly stronger electromagnetic fields that produce undesirable coupling paths to adjacent devices.

In addition, the conductive interconnection comprises a single metal layer deposited on the dielectric substrate and the relatively small section of the conductive interconnection limits the current carrying capacity of the probe.

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